Process for producing tetrachlorethylene



Patented Sept.16, 1941 UNITED STATES PATENT orrics 2,255.15: rnocnss roa r n inucmu ramcnm Georg Basel and Erich Schaeiier, Bnrghau'lm,

Upper Bavaria, ander Germany Wacker Geseilachait iiir ,assignontom-Jlex- Eiektroohe mische Industrie G. m. b. 11., Munich, Bavaria,

Germany, a corporation No Drawing. Application February 19, 1

rial No. 191,575.. In Germany June 10, 19 a cam. (01. zoo-cs4) This mvenam'i relates to the production oi tetrachlorethylene and hasrior its object to prov vide a simple and eflicient process ior this pur- The invention resides in the production of tetrachlorethylene irom acetylene and chlorine. The process consists essentially in passing a mixture oi these two gases in about the ratio oi 1.:3

. taxing the reaction chamber in order to dilute the mixture and to prevent the iormation oi soot or undesirable by-products through heating oi the contact surfaces to a high temperature. I

as a rule about three to eight times the volume of diluting gas, a. g. hydrochloric acid gas, is added to the acetylene-chlorine gas mixture.

' stances which promote the absorption oi chlorine and the splitting oi hydrochloric acid in order to increase the eiilciency and duration of the .contact suriaces; ior example, such substances as chlorides oi bivalent metals, e. g. copper chlorid and the like, are'suitable for this purpose.

Example 1 v The catalyst chamber o! a volume oi 500 cubic cms. is filled with activated carbon, and

a temperature of 300-400 C. is maintained. A gas mixture composed oi liters oi chlorine, 10 liters oi acetylene and 120-150 liters of nitrogenis passed through said catalyst chamber in the space of one hour. Since all the acetylenebe comes converted with the chlorine, a mixture consisting substantially oi. tetrachlorethylene vapor, hydrochloric acid and nitrogen leaves the reaction chamber. The tetrachlorethylene may be readily separated by cooling. The hydrochloric acid is removed from the waste gas, so that the nitrogencan again be added to the mixture of chlorine-acetylene gas required tor the conver- The adjustment of the reaction temperature may be controlled also by a corresponding addition oi diluting gas, and also by cooling the gas mixture or the-individual components thereoi which enter the reaction chamber. In order to obtain tetrachlorethylene from the reaction gas product the latter is cooled after it leaves the reaction chamber, so that the tetrachlorethylene is condensed. However, the tetrachlorethylene may also be separated in other ways, as through adsorption and the like. The conversion occurs practically quantitatively, with the generation oi tetrachlorethylene as well as hydrochloric acid oi great purity. The application oi overpressure renders possible a reduction in the size oi the reaction chamber, but in general such procedure requires more expensive equipment. with the use oi a vacuum there would be danger of oxygen entering at leaky points, which might occasion an explosion.

- chamber.

or activated carbon or silica gel the tetrachlor-,

The reaction temperature is determined inaccordance with the dilution oi the reaction gas with hydrochloric acid and the mixture; in general a temperature oi 300 to 400 C. has been iound suitable. Dense bodies, e. g. china or glass shads are suitable as contact. surfaces, but porous contacts, particularly highly active ones, such as animal charcoaL'charcoal, silica gel and the like are in general preferred. They -sion. 11 the gas entering the reaction chamber is first cooled, the nitrogen addition may be reduced. The yield oi tetrachlorethylene is and higher.

Example 2 The catalyst chamber is filled to a volume oi 2.5 liters with a catalyst consisting of activated carbon which is impregnated with barium chloride. The gas mixture, passed through the catalyst chamber at a temperature 01300-4 0 consists of I t Liters Acetylene 35- 40 Chlorine I 100-120 Hydrochloric acid gas- ..-about 1000 A mixture of tetrachlorethylene vapor and hydrochloric acid gas emerges irom the catalyst By cooling or adsorption by means ethylene may be separated. Upon cooling. a part of the hydrochloric acid gas may again be suitably added to the chlorine-acetylene gas mixture required for the conversion. The output in tetrachlorethylene amounts to and more.

By using elevated pressures a somewhat smaller catalyst space is suiiicient.

It will be evident that various changes may bemade' in the details oi the ioregoing process without departing from the scope and spirit oi e uitably provided or impregnated with sub- 5 the invention as defined in the appended claims.

I2 f The invention claimed is:

1. Process for producing tetrachlorethylene which comprises passing a mixture of acetylene 3 and chlorine over contact surfaces at a temperature of 300-400" C. in the presence of a gas which is inert to the reaction and in the absence of water.

2. Process for producing tetrachlorethylen which comprises passing a mixture .of acetylene and chlorine in the ratio of about 1:3 mols over 3. Process for producing tetrachlorethylene hydrochloric acid gas and in the absence of water.

4. Process for producing tetrachlorethylene which comprises passinga mixtureoi. acetylene and chlorine over porous contact surfaces heated 1 contact surfaces heated to a temperature of 300-400 C. in the presence of a gaseous diluent 3 which is inert to the reaction and in the absence get water.

gwhich comprises passing a mixture of acetylene and chlorine over contact surfaces heated to a .temperature of 300-400" C. in the presence of to a temperature or 300-400 C. in the presence of a gaseous diluent which is inert to the reaccontact surfaces. are treated with a chloride of a bivalent metal.

.8. Process according to claim 4 in which the contact surfaces are treated with a chloride of a bivalent metal.

9.. Process according to claim 5 in which the contact surfaces are treated with a chloride of a bivalent metal.

GE'oaG BASEL. ERICH SCI-IAEF'FER. 

